The research to be pursued is directed towards understanding the essential reactions in virion assembly and the structure of the proteins involved. Using ts mutants four major projects will be developed: 1) Identify and characterize the immature forms during the initial stages of assembly: 2) Study the mechanisms of processing pVI, pVII, and pVIII precursor proteins and the nature of the modification of the IIIa protein in virion assembly; 3) purify, characterize and determine the function of the non-virion 100K protein; and 4) Study details of the chemical structure of fiber and penton base proteins and the reactions of these two capsid proteins in virion assembly. BIBLIOGRAPHIC REFERENCES: Carter, T.H. and Ginsberg, H.S. Viral Transcription in KB Cells Infected by Temperature-sensitive "Early" Mutants of Type 5 Adenovirus. J. Virol., 1976, 18: 156-166. Straus, S.E., Ginsberg, H.S., and Rose, J.A. DNA-minus Temperature-sensitive Mutants of Adenovirus Type 5 Help Adenovirus-associated Virus Replication. J. Virol., 1976, 17: 140-148.